1. Field of the Invention
The present disclosure relates to a key pair management method and an image forming device which are adapted to manage a key pair for use in secure communications.
2. Description of the Related Art
In recent years, when secure communication between an image forming device and an external device, such as a PC (personal computer), is performed, a key pair in a public key cryptographic system is often used in order to protect the data for authentication of the identity of a communication partner and the data generated by encryption. It is known that, in order to secure the safety of the secure communication, it is necessary to generate a key pair having a key length that is larger than a fixed number of bits.
For example, there is a known cryptographic system. In the cryptographic system, when a printing device is powered on, it is determined whether data of a key pair within the printing device exists. If no key pair data exists, a key pair is generated and stored in the printing device. If the key pair data exists, it is further determined whether a secret key data is damaged. If the secret key data is damaged, a new key pair is generated again and the secret key data is updated. For example, see Japanese Laid-Open Patent Publication No. 2005-303676.
However, it is also known that the time for generating a key pair in a public key cryptographic system is increased in proportion to the increase in the key length of the key pair. Hence, if the key length of the key pair is increased to ensure the safety of the secure communication, the time for generating the key pair of the public key cryptographic system is further increased.
For example, in a case in which a key pair of a public key cryptographic system within an image forming device does not exist, secure communication cannot be initiated until the generation of the key pair of the public key cryptographic system is completed. There is a problem in that, if the key length is increased in order to ensure the safety of the secure communication, the time for generating the key pair of the public key cryptographic system is increased and the waiting time for the start of the secure communication is also increased.